Another of the planet's largest islands, Papua stretches over two thousand kilometers from tip to tip. Of geologically recent origin, the island's climate ranges from permanent snowfields to stifling rainforests, with a grass-covered mountains running along its length, thousands of isolated river valleys, and impenetrable para-mangrove forests on its extensive coastal plain. Separated from the continent that pushed it up from the seabed by a shallow narrow strait, Papua is home to species and clades originating in Australia, and a few that have managed to hop over Wallace's Line from the west.